Disclosed herein are chemical preparation of oligonucleotides, chemical entities useful in such preparation, processes for such preparation, and methods of use relating to the chemical preparation of oligonucleotides. Further disclosed herein are novel universal solid supports and phosphoramidite building blocks for oligonucleotide synthesis on solid phase that effect the removal of 3-phosphate moieties during the course of oligonucleotide deprotection.